Cray announced on Wednesday that it will pay $15m (£8m) in cash and 12.7 million in shares, which at closing price that day totalled $115m. But in trading on Thursday, Cray's stock price dropped 69 cents, or 9 percent, to $7.26, lowering the total value of the deal from $130m to $107m.
Both companies' boards have approved the deal, which is expected to close within 60 days, Cray said.
OctigaBay is working on an Opteron-based machine that links groups of processors directly to each other. While the supercomputing market is being remade by clusters of low-cost machines, those typically use systems with chips that communicate through more indirect channels.
OctigaBay's technology comes at a price, however; the company's 12K machine will cost between $100,000 and $2m, Cray said. The 12K has 12 processors devoted to computing but can be stacked in a rack with as many as 144 processors, OctigaBay said.
Cray has specialised in exotic supercomputer designs, but it is increasingly relying on more ordinary components such as AMD's Opteron, which is a chip that adds 64-bit features to the 32-bit "x86" chips sold by AMD and Intel. The 64-bit features boost the amount of memory Opteron can use, and the chip has won acclaim for its high-speed HyperTransport communications link and built-in circuitry for controlling memory.
Opteron is at the heart of Cray's Red Storm supercomputer at Sandia National Laboratories. The machine, expected to be up and running this year, is expected to have a speed of 40 trillion calculations per second. In October, Cray said it was turning the Red Storm design into a commercial product.
Cray is betting hard on Opteron: the Red Storm and OctigaBay products will increase its potential customer base and allow it to tap into a market four times larger than at present, the company said.
On Thursday, Opteron got another supercomputing boost with the announcement of support from Quadrics, which makes high-speed networking gear that links separate computers into a high-performance cluster.
Quadrics supports Novell's SuSE version of Linux running on Opteron, including its 64-bit extensions, and its software is tuned for the memory access requirements of Opteron systems, Quadrics said.
Opteron is arriving in the mainstream server market as well: Hewlett-Packard announced Opteron servers on Tuesday, and Sun Microsystems has bought start-up Kealia, which focuses on Opteron servers. IBM has plans for general-purpose Opteron systems, but so far only sells its e325 for high-performance technical computing.
